National Water Account 2018

Region report

Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Reference information

Focus area

Border Rivers

Murray–Darling Basin: Statement details

Water assets

• Water asset volumes in the region at 30 June 2018 were 18,485,356 ML, more than 80% of which are surface water assets.

Storages

Figure S1 Total storage volume in the region at 30 June 2018 compared with the previous 8 years

• Storage volumes decreased from 69% full at 30 June 2017 to 52% full at 30 June 2018.
• The increase in storage last year was the region's first annual increase in storage in 5 years.

Figure S2 Percentage-full volume on 30 June 2018 for each storage

• Storage volumes peaked in mid-September 2017 following rainfall during the winter months and then generally declined for the remainder of the year.
• Percentage full volumes in major storages in the northern part of the region were generally lower than those in the southern part, which reflects the drier conditions experienced across the north.
• More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.

Inter-region claims

• Inter-region claims refer to the volume of allocation remaining on the required annual release from Snowy Hydro Limited to the Tumut River and the River Murray at the end of the 2017–18 year.

• Due to decreased delivery during the 2017–18 year, the remaining claim at end of the year was almost 50% higher than the previous year.

Figure S3 Total inter-region claims from the Snowy system at 30 June 2018 compared with the previous 8 years

• A more detailed description of the inter-region claim from Snowy Hydro Limited is given in the Region Description.

Rivers, lakes and wetlands, and other assets

• The volume of water in rivers at 30 June 2018 decreased from that at the same time last year, reflecting the drier conditions across the region late in the year (see Climate and water), as well as river operations (e.g. maintenance such as opening locks and weirs) in regulated rivers towards the end of June.
• The volume of water in the region's lakes and wetlands and other assets generally changes little from year to year.

Groundwater assets

Figure S4 Groundwater sustainable diversion limits in the Murray-Darling Basin region

• The groundwater asset volume for the region represents sustainable diversion limit volumes as provided by the Murray–Darling Basin Authority.
• This volume at end of the year was 4% higher than the previous year due to a change in the sustainable diversion limits in several areas.

Water liabilities

• Water liabilities in the Murray–Darling Basin region refer to the volume of allocation remaining on licence entitlements at the end of the 2017–18 year. 

• Water supply licences for individual users and environmental purposes have carryover provisions, which means a portion of water allocation that has not been abstracted at the end of the water year can be carried over into the next water year.
• There are no carryover provisions for urban system supply, and salinity and water table management licences. The portion of water allocation that has not been abstracted at the end of a water year is forfeited and the allocation remaining at the end of the year is 0 ML.
• A more detailed description of water allocations and associated water rights in the Murray–Darling Basin region is given in the Water rights note.

Water asset increases

• Total water asset increases for the region was 19,100,818 ML.
• The key item contributing to water asset increases for the region was runoff, which made up approximately 70% of the total water asset increases. Runoff was less than average, which reflects the below-average rainfall conditions across the region throughout most of the year (see Climate and water).
• Recharge: landscape represented over 50% of the total groundwater increases and was also relatively low compared to previous years.

Water asset decreases

• Total water asset decreases for the region was 13,066,180 ML.
• The key items contributing to water asset decreases for the region were evaporation, and river and floodplain losses, which combined made up over 70% of the total water asset decreases.
• Outflow to sea is typically one of the larger flows but in 2017–18 it only made up 7% of the total surface water asset decreases. Outflow was low compared to previous years due to the dry conditions across the region during most of the year (see Climate and water).
• Extraction: statutory rights, which change little from year to year, accounted for more than 50% of the total groundwater asset decreases.

Water flows

• Total water inflows to the region was 18,968,686 ML, which differs from the volume of Water asset increases (19,100,818 ML). Total water inflows includes the volume of water delivered under inter-region claims; total water asset increases includes the annual allocation for inter-region claims.
• Total water outflows from the region was 24,135,570 ML, which differs from the volume of Water asset decreases (13,066,180 ML). Total water outflows includes the flows corresponding to the accrual transactions—allocated diversions and allocated extractions. Total water asset decreases includes the forfeiture of inter-region claims.
• A detailed description on all the water flows associated with the surface water and groundwater stores is provided in the Water stores note.

Unaccounted-for difference

• The unaccounted–for difference is the volume necessary to reconcile the opening water storage and closing water storage with the total water inflows and total water outflows reported in the water accounting statements.

• The unaccounted-for difference value is primarily attributed to uncertainties associated with modelling natural groundwater movement (see Methods), as well as the exclusion of aquifer storage volumes in the account.